/* 
 * A JavaScript implementation of the RSA Data Security, Inc. MD5 Message 
 * Digest Algorithm, as defined in RFC 1321. 
 * Version 1.1 Copyright (C) Paul Johnston 1999 - 2002. 
 * Code also contributed by Greg Holt 
 * See http://pajhome.org.uk/site/legal.html for details. 
 */ 
 
/* 
 * Add integers, wrapping at 2^32. This uses 16-bit operations internally 
 * to work around bugs in some JS interpreters. 
 */ 
function safe_add(x, y) 
{ 
 var lsw = (x & 0xFFFF) + (y & 0xFFFF) 
 var msw = (x >> 16) + (y >> 16) + (lsw >> 16) 
 return (msw << 16) | (lsw & 0xFFFF) 
} 
 
/* 
 * Bitwise rotate a 32-bit number to the left. 
 */ 
function rol(num, cnt) 
{ 
 return (num << cnt) | (num >>> (32 - cnt)) 
} 
 
/* 
 * These functions implement the four basic operations the algorithm uses. 
 */ 
function cmn(q, a, b, x, s, t) 
{ 
 return safe_add(rol(safe_add(safe_add(a, q), safe_add(x, t)), s), b) 
} 
function ff(a, b, c, d, x, s, t) 
{ 
 return cmn((b & c) | ((~b) & d), a, b, x, s, t) 
} 
function gg(a, b, c, d, x, s, t) 
{ 
 return cmn((b & d) | (c & (~d)), a, b, x, s, t) 
} 
function hh(a, b, c, d, x, s, t) 
{ 
 return cmn(b ^ c ^ d, a, b, x, s, t) 
} 
function ii(a, b, c, d, x, s, t) 
{ 
 return cmn(c ^ (b | (~d)), a, b, x, s, t) 
} 
 
/* 
 * Calculate the MD5 of an array of little-endian words, producing an array 
 * of little-endian words. 
 */ 
function coreMD5(x) 
{ 
 var a = 1732584193 
 var b = -271733879 
 var c = -1732584194 
 var d = 271733878 
 
 for(var i = 0; i < x.length; i += 16) 
 { 
  var olda = a 
  var oldb = b 
  var oldc = c 
  var oldd = d 
 
  a = ff(a, b, c, d, x[i+ 0], 7 , -680876936) 
  d = ff(d, a, b, c, x[i+ 1], 12, -389564586) 
  c = ff(c, d, a, b, x[i+ 2], 17, 606105819) 
  b = ff(b, c, d, a, x[i+ 3], 22, -1044525330) 
  a = ff(a, b, c, d, x[i+ 4], 7 , -176418897) 
  d = ff(d, a, b, c, x[i+ 5], 12, 1200080426) 
  c = ff(c, d, a, b, x[i+ 6], 17, -1473231341) 
  b = ff(b, c, d, a, x[i+ 7], 22, -45705983) 
  a = ff(a, b, c, d, x[i+ 8], 7 , 1770035416) 
  d = ff(d, a, b, c, x[i+ 9], 12, -1958414417) 
  c = ff(c, d, a, b, x[i+10], 17, -42063) 
  b = ff(b, c, d, a, x[i+11], 22, -1990404162) 
  a = ff(a, b, c, d, x[i+12], 7 , 1804603682) 
  d = ff(d, a, b, c, x[i+13], 12, -40341101) 
  c = ff(c, d, a, b, x[i+14], 17, -1502002290) 
  b = ff(b, c, d, a, x[i+15], 22, 1236535329) 
 
  a = gg(a, b, c, d, x[i+ 1], 5 , -165796510) 
  d = gg(d, a, b, c, x[i+ 6], 9 , -1069501632) 
  c = gg(c, d, a, b, x[i+11], 14, 643717713) 
  b = gg(b, c, d, a, x[i+ 0], 20, -373897302) 
  a = gg(a, b, c, d, x[i+ 5], 5 , -701558691) 
  d = gg(d, a, b, c, x[i+10], 9 , 38016083) 
  c = gg(c, d, a, b, x[i+15], 14, -660478335) 
  b = gg(b, c, d, a, x[i+ 4], 20, -405537848) 
  a = gg(a, b, c, d, x[i+ 9], 5 , 568446438) 
  d = gg(d, a, b, c, x[i+14], 9 , -1019803690) 
  c = gg(c, d, a, b, x[i+ 3], 14, -187363961) 
  b = gg(b, c, d, a, x[i+ 8], 20, 1163531501) 
  a = gg(a, b, c, d, x[i+13], 5 , -1444681467) 
  d = gg(d, a, b, c, x[i+ 2], 9 , -51403784) 
  c = gg(c, d, a, b, x[i+ 7], 14, 1735328473) 
  b = gg(b, c, d, a, x[i+12], 20, -1926607734) 
 
  a = hh(a, b, c, d, x[i+ 5], 4 , -378558) 
  d = hh(d, a, b, c, x[i+ 8], 11, -2022574463) 
  c = hh(c, d, a, b, x[i+11], 16, 1839030562) 
  b = hh(b, c, d, a, x[i+14], 23, -35309556) 
  a = hh(a, b, c, d, x[i+ 1], 4 , -1530992060) 
  d = hh(d, a, b, c, x[i+ 4], 11, 1272893353) 
  c = hh(c, d, a, b, x[i+ 7], 16, -155497632) 
  b = hh(b, c, d, a, x[i+10], 23, -1094730640) 
  a = hh(a, b, c, d, x[i+13], 4 , 681279174) 
  d = hh(d, a, b, c, x[i+ 0], 11, -358537222) 
  c = hh(c, d, a, b, x[i+ 3], 16, -722521979) 
  b = hh(b, c, d, a, x[i+ 6], 23, 76029189) 
  a = hh(a, b, c, d, x[i+ 9], 4 , -640364487) 
  d = hh(d, a, b, c, x[i+12], 11, -421815835) 
  c = hh(c, d, a, b, x[i+15], 16, 530742520) 
  b = hh(b, c, d, a, x[i+ 2], 23, -995338651) 
 
  a = ii(a, b, c, d, x[i+ 0], 6 , -198630844) 
  d = ii(d, a, b, c, x[i+ 7], 10, 1126891415) 
  c = ii(c, d, a, b, x[i+14], 15, -1416354905) 
  b = ii(b, c, d, a, x[i+ 5], 21, -57434055) 
  a = ii(a, b, c, d, x[i+12], 6 , 1700485571) 
  d = ii(d, a, b, c, x[i+ 3], 10, -1894986606) 
  c = ii(c, d, a, b, x[i+10], 15, -1051523) 
  b = ii(b, c, d, a, x[i+ 1], 21, -2054922799) 
  a = ii(a, b, c, d, x[i+ 8], 6 , 1873313359) 
  d = ii(d, a, b, c, x[i+15], 10, -30611744) 
  c = ii(c, d, a, b, x[i+ 6], 15, -1560198380) 
  b = ii(b, c, d, a, x[i+13], 21, 1309151649) 
  a = ii(a, b, c, d, x[i+ 4], 6 , -145523070) 
  d = ii(d, a, b, c, x[i+11], 10, -1120210379) 
  c = ii(c, d, a, b, x[i+ 2], 15, 718787259) 
  b = ii(b, c, d, a, x[i+ 9], 21, -343485551) 
 
  a = safe_add(a, olda) 
  b = safe_add(b, oldb) 
  c = safe_add(c, oldc) 
  d = safe_add(d, oldd) 
 } 
 return [a, b, c, d] 
} 
 
/* 
 * Convert an array of little-endian words to a hex string. 
 */ 
function binl2hex(binarray) 
{ 
 var hex_tab = "0123456789abcdef" 
 var str = "" 
 for(var i = 0; i < binarray.length * 4; i++) 
 { 
  str += hex_tab.charAt((binarray[i>>2] >> ((i%4)*8+4)) & 0xF) + 
      hex_tab.charAt((binarray[i>>2] >> ((i%4)*8)) & 0xF) 
 } 
 return str 
} 
 
/* 
 * Convert an array of little-endian words to a base64 encoded string. 
 */ 
function binl2b64(binarray) 
{ 
 var tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/" 
 var str = "" 
 for(var i = 0; i < binarray.length * 32; i += 6) 
 { 
  str += tab.charAt(((binarray[i>>5] << (i%32)) & 0x3F) | 
           ((binarray[i>>5+1] >> (32-i%32)) & 0x3F)) 
 } 
 return str 
} 
 
/* 
 * Convert an 8-bit character string to a sequence of 16-word blocks, stored 
 * as an array, and append appropriate padding for MD4/5 calculation. 
 * If any of the characters are >255, the high byte is silently ignored. 
 */ 
function str2binl(str) 
{ 
 var nblk = ((str.length + 8) >> 6) + 1 // number of 16-word blocks 
 var blks = new Array(nblk * 16) 
 for(var i = 0; i < nblk * 16; i++) blks[i] = 0 
 for(var i = 0; i < str.length; i++) 
  blks[i>>2] |= (str.charCodeAt(i) & 0xFF) << ((i%4) * 8) 
 blks[i>>2] |= 0x80 << ((i%4) * 8) 
 blks[nblk*16-2] = str.length * 8 
 return blks 
} 
 
/* 
 * Convert a wide-character string to a sequence of 16-word blocks, stored as 
 * an array, and append appropriate padding for MD4/5 calculation. 
 */ 
function strw2binl(str) 
{ 
    var nblk = ((str.length + 4) >> 5) + 1 // number of 16-word blocks 
    var blks = new Array(nblk * 16) 
    for(var i = 0; i < nblk * 16; i++) blks[i] = 0 
    for(var i = 0; i < str.length; i++) 
        blks[i>>1] |= str.charCodeAt(i) << ((i%2) * 16) 
        blks[i>>1] |= 0x80 << ((i%2) * 16) 
        blks[nblk*16-2] = str.length * 16 
    return blks 
} 
 
/* 
 * External interface 
 */ 
function hexMD5 (str) { return binl2hex(coreMD5( str2binl(str))) } 
function hexMD5w(str) { return binl2hex(coreMD5(strw2binl(str))) } 
function b64MD5 (str) { return binl2b64(coreMD5( str2binl(str))) } 
function b64MD5w(str) { return binl2b64(coreMD5(strw2binl(str))) } 
/* Backward compatibility */ 
function calcMD5(str) { return binl2hex(coreMD5( str2binl(str))) } 
module.exports = { 
    hexMD5: hexMD5 
} 